Electrical-connection cord



0 odei.) M A. H.-M0GULLOOH.

ELECTRICAL CONNECTION (10111).

No. 522,999. Patented July 17, 1894.

THE uoams PETERQ cu, wonmumu, WASNINGTON. n. c.

UNITED STATES PATENT OFFICE.

ALFRED H. MOCULLOCH, OF BOSTON, MASSACHUSETTS, ASSIGNOR TO THE AMERICANBELL TELEPHONE COMPANY, OF MASSACHUSETTS.

ELECTRICAL-CONNECTION CORD.

SPECIFICATION forming part of Letters Patent No. 522,999, dated July 17,1894."

Application filed February 6, 1894:- Serial No. 499,264. (No model.)

To ZZ whom it may concern:

Be it known that I, ALFRED H. MOCULLOCH, residing at Boston, in thecounty of Suffolk and State of Massachusetts, have invented certainImprovements in Electrical-Connection Cords, of which the following is aspecification.

The present invention relates to insulated electrical conductors andespecially to such conductors as are frequently handled and require tobe very flexible and yielding throughout their length. I

An example of the kind of conductors to which the present invention isapplicable is the looping or linking connecting cord which forms a partof the table outfit of a telephone central station operator and which isused for the purpose of connecting subscribers lines with the operatorsinstruments and with one another. Such a connecting cord as is wellknown has attached to one of its endsaswitch plug which is the terminalof the one or two conductors in the cord and at its other end a flexiblemetal terminal, or in some cases both ends may be fitted with similarterminals. The conducting part of such flexible cords has heretoforebeen made of wire, chain, or tinsel, which conducting portion is, forprotection and insulation inclosed in a stout braided covering. With thestrongest and most pliable conductors that have been devised andemployed up to the present time, the frequent bendings and twistingswhich the cord undergoes in the service of a tele phone exchange, causein time the fracture of the metallic conductor within its braidedcovering, giving rise to serious annoyanceand loss of service tosubscribers. Such occurrences constitute one of the chief difficultiesincident to the operation of a telephone switch-board.

The object of this invention is to avoid difficulties of this nature byfurnishing an electrical connecting cord in which the conducting portionhas pliability in the highest degree, so that it can be bent in anydirection and to any extent without fracture or rupture, and to this endthe invention consists in the employment of a column or thread ofmercury, or other fluid conducting material confined in a suitablecontaining tube, and in providing suitable devices at each terminalwhereby the mercury is brought into electrical contact with bindingposts or with electrical apparatus or conductors of any kind.

In the drawings which are attached hereto, Figure 1 is a view of adouble conductor telephone switch cord embodying my invention. Fig. 2 isa sectional View of one terminal of the cord, and Fig. 8 is a section ofa single conductor detached. Fig. 4 is a cross section of the cord andFigs. 5 and 6 are sectional Views of the other or plug terminal of thecord.

In the drawings A represents the connecting cord as a whole; and being adouble conductor cord,it carries two threads of mercury each in aflexible tube a, a. The tubes a a are of soft vulcanized rubber having adiameter of about three thirty-seconds of an inch and an orifice ofabout one thirty second of an inch in diameter. Each tube is providedwith a light braided covering of cotton thread. At each end of the cordmeans are provided whereby the mercury within is brought into connectionfirst with the tip or sleeve side of the plug P; and second, with theexternal metal terminal 1; and primarily the means are the same, andconsist of wires 4 and 9 which are inserted into the orifice at each endof the rubber tube a; at the plug end the wire 9 extends in but a shortdistance, while at the opposite end the wire 4 extends in a considerabledistance for a reason to be explained farther on.

After the insertion of the wire, the outer surface 2 of the conductor istightly wound or whipped with thread or cord 3 for a little distance tocompress the rubber walls of the tubing upon the wire and make a tightjoint. At the plug end, the externally projecting wires 9 are solderedto the connecting eyes '6 which are secured respectively to the tip andsleeve of the plug P; at the other end of the cord A the wires 4 aresoldered to flexible metal terminals 1. The merouryis pouredinto therubber tubes a in any suitable manner.

In order to provide for the contingency of a rubber tube, a, burstingand permitting the mercury to run out, I inclose the said tube or eeaeeetubes, as the case may be, whether a single or double conductor cord, inanother vulcanized soft rubber tube 5, the ends 8 of which are broughtwell over the whipped ends of the tubes at and are in turn whipped overthem with thread or cord; so that if a tube a should burst, the mercurywould run into the outer tube 5. The fact of such a burst would becomeknown soon, as the cord would become inoperative by reason of thecircuit becoming open.

On either side of the tubes at a, I place a solid, flexible, braidedcord 7 to round out the external tube 5; and braid over the whole astout cotton covering 6.

Fig. 7 represents a section of a telephone switch-board provided withtwo flexible cords A A having mercury conductors. G is a bar providedwith means for holding the cords at one end, and for connecting themelectrically to the operators table. The plugs P l are supported uponthe said table, and the cords are kept straight by means of the weight win their bights; p s are the plug sockets in the upright portion of theboard. It is necessary that the ends of the cords A attached at 0 shallbe as high as the upper row of plug sockets in order that a continuousthread of mercury may extend from one end to the other of the cord. Toguard against a disconnection by any lateral swelling of the tube a andthe consequent accumulation of mercury locally, I extend the wire at atthe suspension end of the cord say eighteen inches into the tube a. Insuch a constructed cord, it is necessary that all possible strains beremoved from the flexible tubes a and from the outer auxiliary tube 5,and to this end the whipping 8 put on over the braided covering 6,serves to seal the tube 5 and also to fasten the covering down, thusbringing all strain to bear upon the covering. At the plug end I showadditional means of bringing the strain upon the outer covering. Thelower end of the plug is made in two parts I) and d, the former having athreaded part c which screws into the latter. A portion of this threadis cut away, and when the end of the cord is pushed into the part b tobe connected to the plug, the braided covering 6 is turned over the endof b where the screw threads are cut away, and whipped on thereto withthread, and then the partb is screwed into the part (1, as shown in Fi6, the braided covering thus taking the strain also at this end.

It will be understood that such a conductor as is herein described canbe applied to all the uses for which an ordimary conductor is employed,when the proper connecting appliances are attached thereto; and that theinvention is applicable to connecting cords having single or doubleconductors.

Having now fully described my invention, I claim- 1. A flexibleinsulated conductor, consisting of a non-conducting tube and a column ofmercury contained therein.

2. An electrical conducting cord consisting of a flexible non conductingtube and a fluid conductor such as mercury filling the same from end toend.

3. An electrical conductor consisting of a flexible non conducting tubecontaining men eury and provided at each end with suitable means ofconnection with other conductors, as set forth.

4. An electrical conductor consisting of a flexible non-conducting tubecontaining mercury provided at each end with connecting appliances whichconsist at one end of a connecting plug and at the other of a solidmetal terminal, as set forth.

5. In an electrical conductor consisting of a flexible non conductingtube containing mercury provided at each end with suitable means ofconnection, and an auxiliary flexible tube inclosing the saidnon-conducting tube, as set forth.

6. An electrical conductor consisting of a flexible non-conducting tubecontaining mer cury, provided at each end with suitable means ofconnection, and an auxiliary flexible tube inclosing the said tube,provided with an outer braided covering, as set forth.

'7. An electrical conductor consisting of one or more flexiblenon-conducting tubes containing mercury, provided at each end withsuitable means of electrical connection, suitable flexible fillingmaterial between the said tubes, and an auxiliary flexible tubeinelosingthe said tubes and filling material, as set forth.

8. A flexible electrical connection cord comprising a plurality ofcolumns of mercury; a non-conducting elastic tube inclosing each of thesaid columns; an exterior non-conducting elastic tube surrounding thesaid mercury inclosing tube; flexible fibrous filling contained togetherwith the insulated mercury conductor in the said exteriortube; a fibrousenvelope braided or woven over the said cxterior tube; and electricalconnection devices at both ends of the said mercury columns,substantially as described.

In testimony whereof I have signed my name to this specification, in thepresence of two subscribing witnesses, this 18th day of December, 1803.

ALFRE D H. NICOULLOCIT.

Witnesees:

Gno. WILLIs Prunes, FRANK (J. Loexwoon.

